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ACQUISITIONS - Narrative (Details) - USD ($) $ in Thousands |  | 11 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Nov. 07, 2022 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2025
Business Combination [Line Items] |  |  |  |  |
Goodwill |  | $ 311,106 | $ 314,000 | $ 311,106 | $ 294,485
Selling, General and Administrative Expenses |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |
Business acquisition-related expenses |  |  |  | $ 968 |
Cascade and Northwest Polymers |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |
Cash consideration |  |  | $ 6,036 |  |
Elite Polymer Solutions |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |
Cash consideration | $ 75,981 |  |  |  |
Purchase price of business acquisition | 90,230 |  |  |  |
Purchase price payable | 14,000 |  |  |  |
Purchase price paid subsequent to acquisition |  | $ 500 |  |  |
Goodwill | 18,669 |  |  |  |
Identifiable intangible assets acquired | 68,480 |  |  |  |
Working capital and other net tangible assets acquired | 3,082 |  |  |  |
Elite Polymer Solutions | Customer relationships |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |
Identifiable intangible assets acquired | $ 68,200 |  |  |  |
Weighted average useful life (years) | 8 years |  |  |  |

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